1. Technical Field
This disclosure relates to power usage estimation and, more particularly, to power usage estimation in a processor using digital techniques.
2. Description of the Related Art
Many modern processors are capable of consuming a great deal of power and in so doing may generate a significant amount of heat. If left unchecked, this heat could cause catastrophic damage to the processor. Thus, power management systems have been developed to limit the power the processor consumes and thus the heat generated. In many power management systems, the thermal design power (TDP) for the entire integrated circuit (IC) device is commonly the primary metric that is used to control power consumption by the IC and to ensure that thermal limits of the IC are not exceeded. Typically, if the thermal limits are being reached, or the thermal power reaches a particular threshold, the power management system may throttle the IC by reducing performance. Conversely, if power consumption can be accurately measured while running a given application, and the power used is less than the TDP capability of the platform, performance may be increased by allowing the IC to consume the available headroom in the TDP by increasing the operating voltage, the operating frequency or both.
However, the capabilities of conventional thermal measurement mechanisms have less than acceptable granularity and repeatability in many cases. Furthermore, conventional thermal measurement mechanisms may not consider the dependence of power consumption on frequency. Conventional thermal management mechanisms that may consider a dependence on frequency typically require complex mathematical computations which must be supported by a microcontroller or other complex circuitry and may be computationally expensive.